Process of and apparatus for metering a liquefied gas



Sept. 16, 1952 n. M. THAYER 2,610,471

PROCESS 0F AND APPARATUS FOR METER A LIQUEFIED GAs Fil Aug. 28, 1947 tgl l Patented Sept.V 16, 1952 Y .i .if

jPRooEss oFfANn APPARATUS FOR METERINGA LIQUEFIED GAS Russell'M; 'I.`liayer;rlualo,VL N. Y., assigner, by

mesne assignments,- to Union Carbide and ,Carr bon Corporation, a corporation of NewHYork.;

Application August-2 8, 1947, serial No. 771,039

. 4This' application relates to 'a process of 1 and apparatus 'for accurately `metering .quantities of liquefied gas when transferred from a containerv toy a'receiver and particularly to'v` the metering of a'liqueiied gas having' a boiling point'at atmos-V pheric pressure below 233 K. such as liquid Oxy-'- gen or liquid nitrogen. l Y

The principalY objects of the'fpresentI invention are to provide an improved' method land appar' ratus for meteringexactly the vvamount. of Qa portion ofJhighiyI-vblame *Iiquenedhgas whenV it fis transferredl fromf a container, in lvvhichf'a supply of the liquefied-gas- .is heldat Ia verylow temperature, toa-receiver such as a'storage" container or a gasify'ing chamberiMorefspecic'ally.. it isan'object' of the invention-:to vprovide method? of and apparatus for preventinglfalse registration by a liquid meter' when itis used to meter apor'tion of 'liquefied gasso' transferredff f-lff 'The invention is particularly adi/antageous-v for metering rliquid oi'cygen and liquid nitrogenwhich have Avery V16W-boiling points 'and are difficult toy s t'r'e'jin` the I liquid state. *Whensuch 'liqueed gasesaretransferred fromo'necontainer to anl-` othe'r itis' often essential toiczietermine fthe` exact! amount f transferred, and lvarious unsatisfactory expedientsto determine the amount transferred I' have'been resorted 'tog-such! as Weighing` either the supply vessel or -therecipient before and-fatter' a'qiantity. of`- liquefied gas fis transferred or by measurements of the liquid' .flevel's before and Inforder that? theamount of.. liquefied.. gas transfered may be accurately registered it is-necessary that the movable elements shall'be moved onlyby theliquid being transferred and not by. 1 any vapors.4 The liqueedgas'esare substantially 'f at their boiling point temperatures-and always With such arliqueed gasLany-leaka'g'e of'heatf to the liquid-'causes .vaporizatiom also-any reduction of pressuredon theliquid lil'ewise causesv boiling to. occur.'

.rhusit is found that'any eatieak-to or riaductionr of .pressure onv such liqueed 'gas :before it has passed through'the metering elementsv ofy a meter will result in the passage through thef meter of an ndeiinitenlamoun't -of' vapor With the liquid'. transferred and suchV vapor. Will move the metering elements .f and lcause false-regis'tration. Aocordingto the lpresent inv'n'tionrthis diiculty? i-savoi'ded by Inaintainingthe metering elements after 'thetransfenf Vbutftlvie former l.is 'extremely f inconvenient if 'accuracy is'requi'redand the-latter: methodv Lis* subject to lco'nsiderable inherent finauraciegfi 'Jv. .f :i ."fg, :i L; l

"According to the present invention thefqu'an'-rv tity of liquefied gasv transferred' fis metered by Y Y passage' through the meterin'glfelementsif a positive f di'spiacementv|` liquid nieterzv .of- A al type especany 'adapted to therhadiing-oi the.- partic-V ular'low'temperature liduifvedigasto be meteredr Such a' meterV has metering elemntsincluding a meteringchamber with movable lelements in! 'thecria-mbr salaires -pijstcnsor anutatmgpiate; r1.

rotary'ele'inents'ythe mv mentfoffvvhichfis ni; exfact'proportion to 'the vvo'lurn t ic ainuntflof materiai'lffpassd: throghrthe hamben i frnej am unt 'f-the'mat'erial 'passedthr'oug'h the meterf isr'cordedby a registermechanismthfatis 'drii'feiiv by" the movable ''elerne'nts Al 'suitabrlfei construe# tin of meterforlidui'dfoxygen orfliuid nitrogenv is s'inlfartoftl'atf described'fin my' copending A'appiication'seriai--Noztosgzvo iedfoctoefjzaisis; which issued November l6,`1948,ffasi`Patent No2- of `'the meterconstantlyat `the` 110W temperatureof the liquefied gas/tc' be'transferr'ed. The liquid 'line to the inlet of thefmeterislikewise'cooled toA such low temperature b'efore'ftransfer 'of li'quidisv begun anda-the. transfer j'o'fliquid from. 'ion'e container to' thelother'- is "then` carried' out in such a manner 'thatfiioappreciable' oreffective reduction of pressuron' the liquefied gas occurs, i at least untilfafte'rpassage through the meter.' fj fThe maintenance ofthe meter chamber iand metering elements therein at the'low temperature is preferably' effected "by mounting` the` metering chamber inheat conducting relationwith'or in contact with a body of the liquefied gas.- VThis' may'fbe done inl various waysfforiexamplaby mounting' the metering chamber'inor on areceivingvesse'l which contains-a portion ofthe liquefied` gas Yremaining 'from-fa previousv charge so that the meteringE chamber is inhea't exchange rela;r

tion WithI such portion/of 4liqueiied gas, or'by mounting the meteringy chamberin or o'n'ithe inner` vessel of a! supplyfcontainer holding 'the' supply.: oifg the'nli'quee'dr gasi.- )in 'eitherjof` "th-ese embodiments :the meter chamber canfb'ei in thermal* contact ivithfltheiliquid-itselfl or "-vvithl"y i the vaporfwhichl is immediate'ly-fabove'Vv the liq-Q uidi'and in heatflexcha'nige therevvithi' In'a" third embodiment the metering chamberis's'ubmrg'ed body orii'quidthe supplycontainer;l faire Yaarden the cooled meter is carried out so that the presy sure on the liquid is higher than the pressure at which the liquefied gas would boil at its existing temperature. 1n other words, the liquefied gas passed through the cooled meter is at least slightly subcooled. The desired amount ci subcooling is preferably attained by obtaining a non- Y equilibrium pressurerincrease of theliquefied gas up to a point at the discharge side of the meter. Y

Such pressure increase may be provided by pressurizing the supply of liquefied gas in the supply following specification and the accoirlpanying embodiment showing theineter mounted on a chamber connectedin liquid communication with the-'supply container; andV Fig; 3f isadiagrammaticfview of` stillanotherV embodiment showing the; metermounted inthe; supply container.`

Referringnow to the drawing, andparticularly toFig. 1, abody'of liquefied gas I-ilf'is shownpheld Within the inner vessel II of; a supply container generally indicated at A, ay receiving container being generally indicated at B. The supply container; mair be of customary construction, in whichfthe inner vessel.l IzI; issuspended or otherwise supported within; an external casing I2 providin'gan insulating space completely surrounding-ithe inner vesselq which space may: be iilled with insulating mater'alIS of ai. character that: is ver/'YV eiective for-'reducing-the iiow of heat lto thev coldlbody of liquid; In, The inner vessely Il may be provided with/customary lling connec-` tions,v liquid level test' connections,v and relief valves, allof whichfarel not' shown ingthezintjerest of clearness.orthedrawinge VThe receiving container B. mayfbe-of anyl cus,- tomary c,onstructi'on and; in; the embodinflentv of;

1 is preferably of, the insulated' type com-- prising an inner vesselI I-II- which* isY supported Within` an outer casing;Vv I5 ,providing aspace lled with insulation I6V aroundthe-inneryvessel. The inner vesselv I4 may` bef provided with liquid` and vapor. discharge conduit-sf as` required; for; utilization oi the liqueedl gas. Such' withdrawal conduits are not illustrated-i inl the interest of clear:` ness'of the drawing; i

A meter forliquefed gas is diagrammatically indicated at M. Asi previously statedysuch metermay be of the typev describedY in myr aforementioned Vpatent application except: that the, cooling jacket .surrounding themetering` chamber is/unnecessary.v In thefembodiment ofrl Fig;4 l thev metering chamber IiIro'ik thefmeter Mis vmounted liifrom containerlA to receiver B', there is provided a transfer conduit I9.

tom ofy inner vessel II by alternative branches 2I and 22. Branch 2| has interposed therein a stop valve 2I and branch conduit 22 has interposed therein a stop valve 22' and also a pump for liquefied gas shown diagrammatically at 23. For liquid oxygen, a suitable pump may be similar toV4 that described in U. S. Patent No.

' 2,340,747 issued February 1, 1944, to O. A.k Hansen.

Conduit I9 is coupled to an inlet connection 24 u that passes through the inner vessel I5 to the inlet of the metering chamber I'I. Also connected between the inlet connection 24 and the vapor' space of the inner vessel II is a vapor returnline 25,.' whichy is employed when priming 1 the pump23 andwhen cooling the transfer convduit I9. Conduit 25 is provided with a stop valve 25 and conduits I9 and 25 may have dis-l connectable couplings 24 interposed therein when', theI supply container A is portable. The discharge side of the meter chamber II is pro# vided with a. connection 26. having; a control valve '26 thereinfandbranches 211: andA 28 connecting.I

respectively toA thevapor space. and the liquid space of1 the:- ninner vessel I.4. These vbranches respectively ared provided with` stopV valves 21' and 28-1 y An alternative means lfor; pressurizing the liquefied gassinV the supply container is provided by aV linel 29 connecting theli'quid outlet 2D with a vaporizingmcoil 30, theV vapor discharge sidegof which is connected `by aconduitSII withthe vapor spaceof; the innerl vessel II'. Theaconnection 29 is provided with a stop valve 219',

In` operation, a Y small remainder of.y liquened gas is usually in the inner vessel I4 so that the vaporsv thereof will` keep; the meteringv chamber [1f-very cold., Whenit isy desired toaddl a specic amount or liqueedf grasV tothe receiverr B, the.-

The transfer conduit Iis connectedtoan outlet 20 from-,thecqbota 75` supply container-A isV coupled toY the receiver B- by*l thev COnduits I--and;,25j at couplingsy 291". The valves;; areadjusted so that valve4 2E! is fclosed,

and' valve 22 is open so that: a1 flowofliquidlcan occur .through the;L connection 2D,Y branch 2.2 vand pump: 23;,.thetransfer-conduit: lzmaifid` the,returnT cond-uit 25:, Portionsgof liquid-enteringtheV pump 2.3;Wil-l c o olfit down to;operatingatemperature and circulated around and; back; tot the: inner vessel A Ii);- so that; the; conduit; I8i` up; .to-i its: connection with the,V conduit 2st willi`- be-jcooled to thetem peratureci the; liquefiedggas; Valve 6;" may then.

be. opened and;.valve 25;" closed; Valves-2,11' andY gas;` space; goethe liquidl space of,v the inner vessel Maasqmaybe desired;vl according to whether, the: Y

pressure inthek innerveeselz Ill,v is to be increased,

kept constant, or decreased, the decreasefinpresf' sure being eiected; if;v desired by heat'y exchange., between the inflowingliquid through branch. 2`I Y and the: vapor` in` the44 innerz vessel, I4`; rIhe` valve. Y2t! isgadjusted gso.,;that1fiti is-wide open ifthe pres-r sure the vessel I4 is higher than the original. y pressureiinthe'innervessel I-I,or if-theipressurev in .theiinner vesselWshouldfbelower,y then: the valve 2 6V isfadjfusted .td-throttle; t-he.-liqui'dY suficientlyl to; maintain ai pressure onV theA` liquid-V owing through the. meter. II:H which` is atfleast slightly higher than thapressure of .the liquid.

may be disconnected.

An alternative mode of operation omit'vstheifse liquid will flow through branch. 2I into the lower partioflconduit I9. v .The vaporizationof liquid in thei-'lowerfpart of.. .conduit I9 will lcoclzthe conduitfand .the cold vapors thereof will passup and through ythe iconduit .25 so that the entire transfer? conduit .willi .be.. cooled. The valve 25- isthenclosedand .thelvalve 26 opened, then'by.

A pressurxdiierence, liquid-wi11 flow` through the outlet ZIJ-the branch 2 I, transfer conduit :I 9, and the" inlet v4to :the meter chamber I 1. The` valves 265.12131?, 'an'dg28fJare'adjusted as before so that therei'sno effective reduction of pressure on the liquid at least until after it has passed through the' metering. chamber' I1.. .The small pressure reduction due to pipeline friction is lessthan the non-.equilibrium pressure increase created in the ntairier nira'nd :therefore/ .such Asmall pressure reductinlisgnot effective' to cause vaporization. If the pressure acting on the liquid body -I fshould fallso kthat'sit is insuicient to drive liquidover co-the containerlB,' the:.va1fve 29 may beopened suliicieitlyto-buildthe. pressure to the desired "Ilnl the embodiment illustrated in Fig.. Zthe' liquefied gasrec'eiving device isnot illustrated las itlm'ay be of any kind customarily used such asa liquidgasifying chamber, a liquelied gas storing eontainer-or a liquid `vaporizing coil connected to.falgas'receiving means.' .In the figures.' corre. spnding I. elements are'Y 'designated' .by similar reference numerals; ."'Thus the body of liquid I0 is eld within 'aninnervessel II supported in'an'd surounded-byinsulation I3'. yThe meter M is mounted vso l that f its Imetering elements I1 are housed within an' auxiliar'yfliquid holding chamberi33v` that holdsa portionrof the liquefied gas bodyvllgsuch portion being maintained inthe chamber V'33 b'y'connections 34and 35, connection' 34A fproviding constant? communication between the bottomufftnechamber 33 and the outlet 2n vof the innervessel I Il andv connection 35 providing constantcommunication between an upper 'portion-ofthe vvchamber 33 land 'the inner vessel lI I atfaj'fpint. higher: thanzthefouuet 2n.: A liquid transfer-'- conduit 36 is connected between the outlet-'lj2'0fand` the inlet of the metervI1. Conduit 36 has nt'erposed thereiniffa' stop -valve 36? anda liquidflpump 123.! A--vapor return line 31 is connectedto the'conduit 3I?V on the dischargeside land-having' `a"' stop valve 38 is also provided. Adischarge Vor delivery connection 39,'provided with a control valve 39', conducts the liqueed gas from..:thei`liqueed Vgas meter I1 through theV walll Valve? .adjustable bac pressuremnthefmeter.

- l I vthisfemlcmdimentitlie;.champerfiitisheavily.

6 insulatedby .a portion of theinsulation .I3 which isV contained; within an extension 40 of. the outer casing II2. 'Ihe chamber could'be separately insulated providedzthat the connections-.34 and Werealso adequately insulated. Valvesand the like which are within the insulation are provided With. operating means extending to the outside of the insulating casing for convenience of operation. L v

. Operation of this form of .the invention is similarto. thatpreviously described in connection with.Fig.-1,' lbut .the opportunity for more .thorough insulation .makes .it easier to precoolthe transfer line. The meter. is kept cold by the lique-V ied gasin the chamber 33... .Any vapors .produced in .chamber 331 are' discharged throughA the: connection 35 to the inner Vessel I I. Valves 36? and 31 are opened and the valve39. is. arrangedor adjustedpto maintain a back pressureonanyliquid tending to pass through the. discharge iline 39.- The pump, .[23 is startedand liquid willflow-from the outlet 20 through'the'conduits 35 and 31 until the pump is .Drimedand the conduit 36 is cold. Valve 31' isV then closed. and the liquid .will .be discharged'from the metering chamber I1 and passed through valve 39. When a sufficient amount of liquid has passed, as indica-ted;accu: rately bythe register I8, the pump is shutdown andjthevalves are closed.-

,If the pumpyishot to be used, the valve 36'- Will remainclosed and the valve 38 is opened.v Valve 31' may also be opened to insure that the line 38 is cold. Valve 29' is thenvopenedfor a sufficient time toqbuvild a pressure on theliqud body Insufficient to overcome any back pressure y in the recipient connected with the delivery co'n` duit 39. Valve 31 may' then be closed and the liquid will ow, due to the diierence of pressure,-r through conduitN 34, by-pass 38; vmeteringchamber I1, and the conduit 39,' valve 39 being adjusted as previously described.:

'In the embodimentof Fig; 3, the metering chamber -I1. of the meterM is mounted in-.the top of the Ainner vessel I I of .the supply container. The register .I8 of the meter is disposed out; side of the insulating casing I2, thus the meter` ing. chamber I1 is kept cold bythe vaporsfa'bo've thebodyof liquid Ill. Alternatively the metering chamber I 1 -could be so positioned that itis con'. stantly Vimmersed in the liquid vof the. body .of liquefied gas I0. In this `form of theinventi-on a transfer conduit 4I is connected between the. liquid outlet 20 and the inl-et 24 of the metering. chamber .I1. The. conduit '4| has interposed therein. a -stop valve 4I' an-da liquid pump 223.; The discharge conduit |39 leadsfromthe outlet of the metering chamber I1 through the container wallstoa.receivingvmeans int-o .which the lique-. ed gas is tobe transferred, such receiving means being not shownrin the interest of clearness; The conduitv I3'9 Vpreferably has .interposed therein a check-valve 45 and -a back pressure or control valve. .I 39; :2W The. `upper. part: of the conduit. 4 I is "connected: .to .thefvapo-r `.space yabove the liquid IVO-@byfa connectionAZ` controlled by afstop: valve; 42 A liqui-d .educt'iongpipe 343; also .is connected tothe conduit .4I1andhasan Qpeningirrthezlowerpart ofthe liquidffspacesofithe -inner.ix'ress'elif.IfI'z Avalve 43 controlsithei'lip'ei43,..` :1' .1 c the iop'eration; of zthe :embodimentoi- Fig.- A3, when-iisin'g; thezliquid pump 223, valves-.14 ifland 42'. .are -npened-.and .thefpump started: andltrun'; until it'ris' p'rimedand` theconduit 4.I..is .coo'ledf by; the: oW oi`..liquid1.from; outlet 2li-through .fconi duit 41|? ,and'connection Y .42 back c int-o :thelirin'en vessel-f H?. Whenthe. valve 421 isclosedlandvalve |39. opened, liquidlwilltowthrouglrthexmeter- Y ingfchamber I'Ifandoutthrough pipe E39; If. the recipientepressureiis high. enough valve |.29-may beopened Wide an'dnliquid. will iiow through' the checkvalve 45". only when its'` pressure exceeds thatin. the recipient. It, -howeventhe. recipient pressure. is lower. thantheoriginal pressure'. of the supply vessel, the valve 35 is adjusted. tom-ain-y tain. the. desired'` back'. pressurelon themeter. IIZhu-s,` novaporsv will form inthe metering chamber.' |11 because.v itis initially suii'iciently cool and becausezthe ba-ckvpressurefvalve 139! avoidsiany-f reduction' of pressure until' after the! liquid' has passed through. the meteringlchamber I1; .It the. pump.- 23r is. not; to be used,.valves-4l and' 42? rem-ain closedl and valve 29 is opened` enough'. to. evaporate some liquid in the' coil 33? to momentarily raise the gasV pressure intheinner vessel. III to ai` value above the pressureI in' the reoeivingf device. Whenvalve 43 is then opened and. valve. |39 opened orwadjusted, liquid will ovv through the pipe. 43. and through the precool'e'd4 metering chamber ITS and out the discharge .line |39.' alsoy without the occurrence of' vapor i'n` the portions`v of liquid flowing through. the-metering. chamber l1.- y

Itiwill be understood thatY the apparatus described herein may be m-odied, and' that other changes may be. made without departing from the;` spirit and scope of this invention asf donned inthe: appended claims".`

What isfcl-aimed is:

1..A.pr.oc'ess1 of measuring" accurately a" qua-ntitvof' liquefied gasl of the type-havingaV boiling point atzatmospheric' pressure below'2'33v`i* K. Whentransferred from asupply source at low temperatureto a receiver through themetering elements of; a. volumetricliquidi meter adapted` to register the; amount"l of a: liquefied gaspassed there`` through, which process.comprisesA provi-ding; Vcontinuous heatr exchangebetween.. aah-ody. of said liqueed. gas; andthe metering elements. of'- said meter to maintain said metering elements. sub1- stantially` at the. temperature of the liquefedgas to'be.: transferred, such. continuous heat` exch-ange beingstablished prior tothesinitiationoiany flow. through. the metering elements;4 and. p'assingisaid quant-ity of liqueed-gas from-isaidsource `through theioold metering. elements to said'receiver; while maintaining the pressure on. said quantity: oi liquefied. gas during: such'. passagelat a value at' least; slightly higher than. itsfvapor pressure at` the: temperature of theliquidat the source; where-f the; actual. quantity of said .liquid .transferredT measured:.as liquidi a 2f.. Afprccessfomeasuring:accurately'a Vquantity; off liqueedgaslof the? type; having .-aboilin'g. point at; atmospheric pressures' below. 2335 according. toclaim-il. in w-hich .said continuousi-heatzexchange eieoted'; with v'ap'on' Which. is in equilibrium withthepliquefied. gas:r Y.

A: process of measuring: accurately a quanti.'-A t'y. of, liqueiied gasf of thei typefl'iavingl a-.boi'ling pointl at'.atmospheric"pressure.below 233 K.. :ic--` cording to claim; 1. ingwhich'. said heat exchangeis; effectedfwith. a. portion of-. said liquefied.. gasf that; 1. isv inV constant communicationV with the. liquefied gas in thesupplwcontainer.

. 4; ilpparatus'for. accurately measuring a. quanti'ty of liquefied .gas ofthe type-having." a, boiling" point/at atmospheric.pressuref'belovv233 K. in'

a: system including.a;..s11ppl5'r.source?ofthealiquesr fied gas. atA low*Y temperature; a. Iiqueed gas rel-f cei-vinggnieans; a transfericonduit.; connected between: said. source: andi.- said. receiving; means; means: forrcontrollahly eieoting ai iiovvVV of aa desired portion of. ther liqueiiedv gas. through; the transfer: conduitfroni the source to: the receiv-v ing means, said .system including; heatfinsulated chamber-f holding ai. body of theliquefiedgas at' the. lovv.Y temperature independent. .of said. transfer: conduit,. said'. apparatus comprising. avolu-Y metric liquid Vmeter having a meter' chamber and. metering elements.v therein. interposed dii-- rectly in saidtransfer conduit;y the metering ele-f ments: being` adaptedtdregister the.. amount of liquefied. gas p'assed through the meter. chamber: and. means forY mountingysaid. meter. chamber in said. insulated chamber. holding; 'the bodyofliquefiedgas. and in position to provide continu. ous heat.. exchange between said z metering ele'- rnents and said bodyo liqueed gas; andmaintainv the metering elements.: substantially; atg. thev temperature'` of` the. liqueiiedfgas prior tol and during alftransferoi'A liquid. through said' transfer conduit; i l

5.-. Apparatus forgaccurately` measuring: a,l quan'- tity or liqueedgasfoi. the; typehavin'g a. boiling;v

' point at. atmospheric pressure belovvr233` ace;

cordingfto claim 4i in; which saidbody of; liquid is: at least a parti of theiliqueedgas `of Athessuppl'xrsource'. f .1

6. .Apparatus fory accurately measuringj a quan.-` tity oftV liquefied gas ofi the.:typefhavingarboiling point' at atmosphericxpressure below233"' Kewhen transferred from a supply container holdingthe liquefied gas at lovv. temperature.y to a receiving means; nwhichz apparatus comprisesV a.l transfer;

" conduit; connected between the liquid spacefoiv said' supply containerandsaid. receilvingimeans;` means. for controllably effecting, a* flowfV oi? e. desired portion; of liqueed gasl vfronrthey supi ply-'container to thev receiving.. means; a. volu metricliquid meter having? a meter: chamber and: metering-v elernents therein.- intcrposedyin. Isaidtransfer conduit, the metering` elementsfbeing adaptedrto. register theamount of liquefied gas passed through the. meter.' chamber and mea-ns fori mounting said' meter; chamber in' a portion of said supply: container; and in; position to provide continuous heat exchange between` saidqmeterf-v ing. elements and gas material inlsaidgsupplycontainer,.and maintain: the meter elements; sub.-4

, stantia'lly atlthe temperature of theliqueed gas.

prior to; a` transfer. of-liquid, through rlem;I

7, i'tpparatus;forl accurately/measuring a-.quan tityof liqueed; gas: ofthe- .type having a' boiling.;I point. at` atmospheric; pressure; belowV 233,?1K. when;

c. transferred fromfasupply container holdingV the liquidmeter` havingiazcmeterY chamber and meter,-

ing," elements 'i therein` interposed. in said' transferr conduit. themetering. :elements being; adapted-to? register Ythe amount: of'liquened: gas.passed1= throughrthe. meterchamber; a. heat.-insul'ated chamberv holding se body: 'of' thew liquefied? gas and connected with ,theA supp'ily containers toi provide? a. free liquid communieationbetweeni.such body ofliquid? and the liquid `ini the supply.' c'on'taixiemj.v andi means forY mountingL saidmeterI Chamberlin. said heat insulated' 'c'iianfibeif.- in neat` v exchange; relation to said body ofliquid!tol'maintainlthei meter: elements. sobsta'xitra-illyl at.th'efftem'parat'.ure

9 of the liquefied gas prior to a transfer of liquid through them.

8. Apparatus for accurately measuring a quantity of liquefied gas of the type having a boiling point at atmospheric pressure below 233 K. when transferred from a supply source at low temperature to a heat insulated liquid-holding receiver chamber, which apparatus comprises a transfer conduit connected between said supply source and said receiver chamber; means for controllably effecting a flow of a desired portion of liquefied gas from the supply source to the receiver chamber; a volumetric liquid meter having a meter chamber and metering elements therein interposed in said transfer conduit, the metering elements being adapted to register the amount of liqueed gas passed through the meter chamber; and means for mounting said meter chamber in a portion of said receiver chamber and in position to provide continuous heat exchange between said metering elements and cold gas material in said receiver chamber previously charged thereinto, and maintain the meter elements substantially at the temperature of the liqueed gas prior to a transfer of liquid through them.

9. Apparatus for accurately measuring a quantity of liquefied gas of the type having a boiling point at atmospheric pressure below 233 K. accordingto claim 8 in which said transfer conduit on the discharge side of the meter is provided with branches, one of which communicates with the liquid space of said receiver chamber and the other of which communicates with the vapor space of said receiver chamber, and valve means for controlling ow through said branches.

10. Apparatus for accurately measuring a quantity of liquefied gas of the type having a boiling point at atmospheric pressure below 233 K. when transferred from a supply container holding the liquefied gas at low temperature to a receiver. which apparatus comprises a transfer conduit connected to the liquid space of said supply container and to a servicing connection connectable to said receiver; means for controllably effecting a iiow of a desired portion of liquefied gas from the supply container through the transfer conduit to the servicing connection; a volumetric liquid meter having metering elements including a metering chamber interposed in said transfer conduit and adapted to register the amount of liquefied gas passing said metering elements; and an insulated chamber holding a-portion o-f liquefied gas in heat exchanging relation to the metering chamber of said meter, said insulated chamber being connected in constant liquid communication with said supply container.

RUSSELL M. THAYER.

REFERENCES CITED The following references are of record-'in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,007,251 Kniskern July 9, 1935 2,015,946 Marden Oct. 1, 1935 2,049,239 Wilcox -July 28, 1936 2,291,678 Benz et al Aug. 4. 1942 2,402,355 Whaley, Jr. June 18, 1946 2,453,766 Thayer Nov. 16, 1948 

1. A PROCESS OF MEASURING ACCURATELY A QUANTITY OF LIQUEFIED GAS OF THE TYPE HAVING A BOILING POINT AT ATMOSPHERIC PRESSURE BELOW 233* K. WHEN TRANSFERRED FROM A SUPPLY SOURCE AT LOW TEMPERATURE TO A RECEIVER THROUGH THE METERING ELEMENTS OF A VOLUMETRIC LIQUID METER ADAPTED TO REGISTER THE AMOUNT OF A LIQUEFIED GAS PASSED THERETHROUGH, WHICH PROCESS COMPRISES PROVIDING CONTINUOUS HEAT EXCHANGE BETWEEN A BODY OF SAID LIQUEFIED GAS AND THE METERING ELEMENTS OF SAID METER TO MAINTAIN SAID METERING ELEMENTS SUBSTANTIALLY AT THE TEMPERATURE OF THE LIQUEFIED GAS TO BE TRANSFERRED, SUCH CONTINUOUS HEAT EXCHANGE BEING ESTABLISHED PRIOR TO THE INITIATION OF ANY FLOW THROUGH THE METERING ELEMENTS; AND PASSING SAID QUANTITY OF LIQUEFIED GAS FROM SAID SOURCE THROUGH THE COLD METERING ELEMENTS TO SAID RECEIVER WHILE MAINTAINING THE PRESSURE ON SAID QUANTITY OF LIQUEFIED GAS DURING SUCH PASSAGE AT A VALUE AT LEAST SLIGHTLY HIGHER THAN ITS VAPOR PRESSURE AT THE TEMPERATURE OF THE LIQUID AT THE SOURCE, WHEREBY THE ACTUAL QUANTITY OF SAID LIQUID TRANSFERRED IS MEASURED AS LIQUID. 